PREFACE 9 



Ottys Sanders, Southwestern Biological Supply Company, The Frog 

 Sewell H. Hopkins, Agricultural and Mechanical College of Texas, 



Animal Parasitisyn 

 Willis Hewatt, Texas Christian University, Animal Distribution 

 A. 0. Weese, University of Oklalioma, The Animal and Its Environ- 

 ment 

 Frank G. Brooks, Cornell College, Genetics and Eugenics 



Acknowledgment is made to Ivan Summers for the excellent art 

 work he has put into the book. Appreciation is likewise expressed 

 to Dr. Titus Evans, Mrs. Ruth Sanders, Miss Joanne Moore, and Mr. 

 Edward O'Malley, ^vho have prepared certain of the illustrations. 

 Finally, the author wishes to express appreciation to the Agricultural 

 and Mechanical College of Texas, and the staff of its Biology Depart- 

 ment for the cooperation which has made the organization of this 

 book possible. 



George E. Potter. 



College Station, Texas. 



